File Renaming with 1.64 beta

I just read in the forum that the latest beta release of Gravity Forms allows file renaming and nicely formatted URLS of uploaded images. I don't however, see any documentation on this feature and, after installing the beta version, I don't see any options in the Upload item that allows me to change file name.
Your demo site has a sample that allowed me to upload an image with an 'ugly' filename and then it sent me an email with the nicely formatted name.
How can I implement this?

I have tried to use the PHP that was posted at http://www.gravityhelp.com/forums/topic/renaming-uploaded-files-before-saving. I added this to my themes functions.php and in the debug text, it clearly shows that it finds the original file, and shows me the nicely formatted name I want to give it, but the function fails with a 'cannot find file in directory' error.

At the end of that post, I read that eventually, file renaming functionality will be added but likely will just be a hook, instead of in the UI, as 'not many users will need this functionality'. I strongly disagree with that idea. Including keywords in image file names is an important part of good SEO practices, and this is why it is so important to ensure that images that users upload have their filenames changed.

Other than that big request, let me say that I LOVE Gravity Forms.

I'm referring to the post by Chris Hajer at http://www.gravityhelp.com/forums/topic/replace-unwanted-characters-from-file-upload#post-35546
He states

The 1.6 version which is currently in beta 3 and available on the download page does a better job at renaming the files. You can try uploading your file here and see what the link looks like in your email confirmation:"

I have a custom PHP script I built for my own uploader (completely independent of Gravity Forms) that works perfectly for renaming an image that a user uploads. Is it possible for me to call this script after the Gravity uploader completes its task?